Neuron activator

ABSTRACT

The present disclosure provides a neuron activator that activates neurons. The neuron activator includes at least one selected from the group consisting of a dopamine production promotor that promotes dopamine production of the neurons, a neuron extension promotor that promotes extension of the neurons, and an amyloid β resistance enhancer that enhances resistance of the neurons against amyloid β. The neuron activator includes 6-methylsulfinylhexyl isothiocyanates or glycosides thereof, and at least one selected from the group consisting of unsaturated fatty acid and polyphenol.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.16/144,641, filed Sep. 27, 2018, which claims the benefit of JapanesePatent Application Nos. 2017-191584, 2017-191585, and 2017-191583 allfiled on Sep. 29, 2017 with the Japan Patent Office, the entiredisclosures of which are incorporated herein by reference.

BACKGROUND

The present disclosure relates to a neuron activator that activatesneurons.

In recent years, researches on dementia have progressed in preparationfor an aging society. Parkinson's disease is one of dementia.Parkinson's disease progresses by degeneration and shedding ofdopaminergic neuron, resulting in decrease in dopamine-producing abilityof neurons.

Therefore, conventionally, various measures have been taken forinhibiting the decrease in dopamine-producing ability of neurons orpromoting the production, for example, as disclosed in JapaneseUnexamined Patent Application Publication Nos. 2006-321737, 2008-19242,and 2015-208282.

The inventors of the present application have made extensive explorationfor substances that are different from those of the prior art and thatpromote dopamine-producing ability of neurons.

Also, various causes are known for an onset of dementia, but many ofthem are caused by damage and degeneration of neurons. Neurons, whichextend long neurites, are specialized to convey stimulus information.Therefore, conventionally, pharmaceuticals have been developed whichinhibit damage and degeneration of neurons.

The inventors of the present application have been developingpharmaceuticals and functional foods using wasabi components for manyyears, as can be seen in Japanese Unexamined Patent ApplicationPublication Nos. 2010-202559 and 2015-051927. The inventors attempted topromote extension of neurons using wasabi components.

In addition, maintenance and improvement of brain function such asmemory, learning skills and the like are required for a wide generation,from the young to the elderly, including students and social workers whostudy for examinations for entrance, certificate or the like.

Diseases caused by decrease in brain function include not only dementiarepresented by Alzheimer's disease but also mental disease such asdepression and delirium. One cause of the decrease in brain function isdeath of neurons. Death of neurons is said to be caused by accumulationof amyloid β and the like. When amyloid β becomes fibrotic andaccumulates as a lump (senile plaque) inside the brain, anomalous changeof tau protein and synapse is caused by the influence. This anomalouschange impairs substance transport inside neurons and informationtransmission between neurons, thereby decreasing brain function.

In recent years, natural materials are being searched that are effectivefor inhibition and improvement of deterioration of brain function. Assuch natural materials, for example, rosemary, rice bran and the like(Japanese Unexamined Patent Application Publication No. 2013-526865),ginkgo leaf, curcumin, astaxanthin and the like (Japanese UnexaminedPatent Application Publication No. 2015-107960) are known. Also, DHA andthe like are known to be effective in reducing amyloid β (JapaneseUnexamined Patent Application Publication No. 2015-147775).

At present, it is strongly desired to further find substances effectivefor inhibiting deterioration of brain function, improving brainfunction, and to investigate applicability to pharmaceuticals.

SUMMARY

It is preferable to provide a novel neuron activator in the presentdisclosure.

In one aspect of the present disclosure, it is desirable to provide anovel dopamine production promotor that can promote dopamine-producingability of neurons.

In another aspect of the present disclosure, it is desirable to providea neuron extension promotor that can promote extension of neurons.

In further another aspect of the present disclosure, it is desirable toprovide an amyloid β resistance enhancer that can enhance resistance ofneurons against amyloid β.

A neuron activator of the present disclosure that activates neuronscomprises at least one selected from the group consisting of a dopamineproduction promotor that promotes dopamine production of the neurons, aneuron extension promotor that promotes extension of the neurons, and anamyloid β resistance enhancer that enhances resistance of the neuronsagainst amyloid β. The neuron activator includes 6-methylsulfinylhexylisothiocyanates or glycosides thereof, and at least one selected fromthe group consisting of unsaturated fatty acid and polyphenol.

BRIEF DESCRIPTION OF THE DRAWINGS

An example embodiment of the present disclosure will be describedhereinafter with reference to the accompanying drawings, in which:

FIG. 1 is a diagram showing results of a dopamine production testaccording to Experimental example 1;

FIG. 2 is a diagram showing results of a toxicity test of6-methylsulfinylhexyl isothiocyanate (6-MSITC) according to Experimentalexample 2;

FIG. 3 is a diagram showing results of a toxicity test of curcumin toPC12 cells according to Experimental example 2;

FIG. 4 is a diagram showing results of a toxicity test of DHA to PC12cells according to Experimental example 2;

FIG. 5 is a diagram showing results of a toxicity test of isorhamnetinto PC12 cells according to Experimental example 2;

FIG. 6 is an explanatory view showing a neuron;

FIG. 7 is a diagram showing results of an extension test according toExperimental example 3;

FIG. 8 is a diagram showing results of a toxicity test of6-methylsulfinylhexyl isothiocyanate (6-MSITC) according to Experimentalexample 4;

FIG. 9 is a diagram showing results of a toxicity test of curcuminaccording to Experimental example 4;

FIG. 10 is a diagram showing results of a toxicity test of DHA accordingto Experimental example 4;

FIG. 11 is a diagram showing results of a toxicity test of isorhamnetinaccording to Experimental example 4;

FIG. 12 is a diagram showing results of an amyloid β neurotoxicityresistance test according to Experimental example 5; and

FIG. 13 is a diagram showing results of a hydrogen peroxide toxicityresistance test according to Experimental example 6.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

An embodiment of the present disclosure provides a neuron activator thatactivates neurons. The neuron activator comprises at least one selectedfrom the group consisting of a dopamine production promotor thatpromotes dopamine production of neurons, a neuron extension promotorthat promotes extension of the neurons, and an amyloid β resistanceenhancer that enhances resistance of the neurons against amyloid β.

The neuron activator of the present embodiment includes (A)isothiocyanates such as 6-methylsulfinylhexyl isothiocyanates(hereinafter, also referred to as “6-MSITCs”) or glycosides thereof, andat least one selected from the group consisting of (B) unsaturated fattyacid and (C) polyphenol.

In the present embodiment, the dopamine production promotor includes atleast one selected from the group consisting of (A) isothiocyanates suchas 6-methylsulfinylhexyl isothiocyanates or glycosides thereof, (B)unsaturated fatty acid and (C) polyphenol.

According to the dopamine production promotor of the present embodiment,dopamine-producing ability of the neurons can be promoted. The dopamineproduction promotor of the present embodiment promotes production ofdopamine by the neurons.

In the present embodiment, the neuron extension promotor includes (A)isothiocyanates such as 6-methylsulfinylhexyl isothiocyanates orglycosides thereof, and at lease one selected from the group consistingof (B) unsaturated fatty acid, and (C) polyphenol.

According to the neuron extension promotor of the present embodiment,extension of the neurons can be promoted. The neuron extension promotorpromotes neurite extension of the neurons.

In the present embodiment, the amyloid β resistance enhancer includes(A) isothiocyanates such as 6-methylsulfinylhexyl isothiocyanates orglycosides thereof, and at least one selected from the group consistingof (B) unsaturated fatty acid and (C) polyphenol.

According to the amyloid β resistance enhancer of the presentembodiment, resistance of the neurons against amyloid β can be enhanced.The amyloid β resistance enhancer of the present embodiment can increaseresistance of the neurons against amyloid β and protect the neurons.

(A) 6-MSITCs, and at least one selected from the group consisting of (B)unsaturated fatty acid and (C) polyphenol are constituents of the neuronactivator, especially of the dopamine production promotor, the neuronextension promotor, and the amyloid β resistance enhancer. Hereinafter,description on (A) 6-MSITCs, (B) unsaturated fatty acid, and (C)polyphenol will be given.

(A) Isothiocyanates

In the present embodiment, isothiocyanates refer to a compound having a—NCS group. Isothiocyanates may, for example, have an aliphatic or anaromatic group as a side chain. Examples of isothiocyanates having analiphatic group include at least one selected from the group consistingof isopropyl isothiocyanate, isobutyl isothiocyanate, 2-butylisothiocyanate, isoamyl isothiocyanate, amyl isothiocyanate, allylisothiocyanate, 3-butenyl isothiocyanate, 4-pentenyl Isothiocyanate,5-hexenyl isothiocyanate, 6-heptenyl isothiocyanate, 3-methylthiopropylisothiocyanate, 4-methylthiobutyl isothiocyanate, 5-methylthiopentylisothiocyanate, 6-methylthiohexyl isothiocyanate, 7-methylthioheptylisothiocyanate, 4-methylsulfinylbutyl isothiocyanate, 5-methylsulfinylpentyl isothiocyanate, 6-methylsulfinylhexyl isothiocyanate,6-methylsulfinylhexyl isothiocyanates (6-MSITCs), and7-methylsulfinylheptyl isothiocyanate. Among them, 4-methylsulfinylbutylisothiocyanate. 5-methylsulfinyl pentyl isothiocyanate, 6-MSITCs, and7-methylsulfinylheptyl isothiocyanate are preferable. An example ofisothiocyanates having an aromatic group includes phenethylisothiocyanate.

In the present embodiment, isothiocyanates include glycosides.

In the present embodiment, preferred isothiocyanates are 6-MSITCs orglycosides thereof.

In the present embodiment, 6-MSITCs include 6-MSITC and 6-MSITC analogs.6-MSITC is represented by a chemical formula below.

In the present embodiment, 6-MSITC analogs include naturally occurringanalogs of 6-MSITC, and synthetically obtained, non-naturally occurringanalogs of 6-MSITC. Examples of 6-MSITC analogs include 6-MSITC (havinga structure of non-oxidized sulfur, that is, a structure containing amethyl sulfide group) and 6-MSITC (having a structure of peroxidizedsulfur, that is, a structure containing a methylsulfonyl group), and thelike.

6-MSITCs used in the present embodiment are contained in Brassicaceaeplants, for example. Among Brassicaceae, hon-wasabi and/or horseradishcontain many 6-MSITCs.

6-MSITCs used in the present embodiment can be obtained by chemicalsynthesis, but may be extracted from plants and purified. Examples ofplants that can be raw materials for 6-MSITCs include Bataceae,Brassicaceae, Bretschneideraceae, Capparaceae, Caricaceae,Euphorbiaceae, Gyrostemonaceae, Limnanthaceae, Moringacea,Pentadiplandraceae, Phytolaccaceae, Pittosporaceae, Resedaceae,Salvadoraceae, Tovariaceae, Tropaeolaceae and the like. Morespecifically, the examples include wasabi (Wasabia japonica) [also knownas hon-wasabi], horseradish (Armoracia rusticana) [also known asYama-wasabi], Batis maritima, mustard (Brassica juncea), broccoli(Brassica oleracea var. italica), mouse-ear cress (Arabidopsisthaliana), shepherd's purse (Capsella bursa-pastoris), watercress(Nasturtium officinale), Bretschneidera sinensis, caper (Capparisspinosa), papaya (Carica papaya), Drypetes roxburghii, Putranjivaroxburghii, Tersonia brevipes, Limnanthes douglasii, horseradish tree(Moringa oleifera), Pentadiplandra brazzeana, pokeweed (Phytolaccaamericana), Bursaris spinose var. incana, white mignonette (Resedaalba), Salvadora persica, Tovaria pendula, Indian cress (Tropaeolummajus) and the like. 6-MSITCs that can be used in the present disclosureare not limited to those obtained from the above plants. All naturalresources that contain 6-MSITCs can be used as raw materials.

Examples of extracting and purifying methods from the above plantsinclude a method of extracting 6-MSITCs from wasabi and horseradishwhich are Brassicaceae plants. A preferred purifying method is disclosedin Japanese Patent No. 3919489.

In the present embodiment, glycosides of 6-MSITCs are compounds in whichsugar residues are bonded to 6-MSITCs. Preferred sugar residues whichare bonded to 6-MSITCs include at least one sugar selected from thegroup consisting of glucose, rhamnose, fructose, and galactose. Glucoseis more preferred. The sugar residue may be either monosaccharide orpolysaccharide, and monosaccharide is preferred. Monosaccharide refersto sugar consisting of a monosaccharide molecule. Polysaccharide refersto a sugar chain in which two or more monosaccharide molecules arebonded. It is preferable that the polysaccharide is formed by bondingtwo to ten monosaccharides. It is further preferable that thepolysaccharide is formed by bonding two to five monosaccharides.

It is preferable that the sugar residues are bonded to 6-MSITCs at apositon of the —NCS group, more preferably bonded to S.

Examples of glycoside of 6-MSITCs include glucohesperin. Glucohesperinis a compound represented by a chemical formula below.

Glycosides of 6-MSITCs can be obtained from plants containing glycosidesof 6-MSITCs, such as hon-wasabi. For example, enzyme reaction of theplants is stopped by a method such as heating (by electromagnetic wave,far infrared ray, calcination, or the like), drying, freezing, enzymetreatment, chemical treatment, and the like. Thereafter, solventextraction or squeezing by water, organic solvent or the like, drying,pulverization, purification, enzyme reaction, chemical reaction and thelike are carried out. Thereby, glycosides of 6-MSITCs are extracted orseparated, and purified. In addition, glycosides of 6-MSITCs can beobtained by chemical synthesis.

(B) Unsaturated Fatty Acid

Unsaturated fatty acid refers to a fatty acid having at least one doublebond. Preferred unsaturated fatty acid has two or more double bonds. Thenumber of carbons of unsaturated fatty acid is not particularly limited,but preferably 12 to 24, more preferably 15 to 24, and furtherpreferably 18 to 22.

It is preferable that unsaturated fatty acid has double bonds at leastin one of ω-3 position, ω-6 position, and ω-9 position. Specifically, itis preferable that unsaturated fatty acid is ω-3 fatty acid.

Ω-3 fatty acid has a double bond at least in the ω-3 position of thefatty acid. Examples of the unsaturated fatty acid having a double bondin the ω-3 position include docosahexaenoic acid (DHA,22:6(Δ^(4, 7, 10, 13, 16, 19))), docosapentaenoic acid (DPA,22:5(Δ^(7, 10, 13, 16, 19))), eicosapentaenoic acid (EPA,20:5(Δ^(5, 8, 11, 14, 17))), and α-linolenic acid (ALA,18:3(Δ^(9′ 12, 15))).

It is preferable that the ω-3 fatty acid is extracted from fish andshellfish and/or fish oil. DHA is included in, for example, blue fish.EPA is included in fish oil of such as cod, herring, mackerel, salmon,sardine, and krill. Among these, DHA and EPA are preferred. DHA is morepreferable.

(C) Polyphenol

In the present embodiment, polyphenol is a generic term for compoundshaving a plurality of phenolic hydroxy groups in a molecule. Polyphenolpreferably includes at least one selected from the group consisting ofcurcuminoid and flavonoid.

Curcuminoid may be represented by a formula (I) below.

(In the formula, Ar represents an aromatic group having an OH group.)

Examples of curcuminoid include curcumin dimethoxy curcumin and bisdimethoxy curcumin. Among these, curcumin is preferred. Examples ofcurcumin are represented by formulas (I-I) to (I-IV) below.

Examples of components having curcumins include turmeric extract,turmeric pigment, or the like.

It is preferable that curcuminoid is extracted from turmeric.Curcuminoid including curcumins can be obtained, for example, byextraction separation from turmeric or the like as a raw material, usingorganic solvent such as alcohol solvent, or by synthesis.

It is preferable that flavonoid is a flavonol represented by a formula(II) below.

(In the formula, X represents —O⁻ or —OH, Y represents —O⁻ or —OH, Zrepresents —O⁻ or —OH, and X, Y and Z together have two or more —OH.Also, n represents an integer of 1 to 4, and m represents an integer of1 to 5.)

Examples of flavonol include those represented by formulas (II-I) to(II-XI) below. Among these, isorhamnetin represented by the formula(II-III) is preferred.

An example of components including isorhamnetin is gingko extract.

It is preferable that flavonoid is extracted from ginkgo leaves.Flavonoid can be obtained by a known extraction method fromflavonoid-containing plants, or a known synthesis method. Isorhamnetincan be extracted from ginkgo leaves by a known method.

It is preferable that the neuron activator of the present embodiment mayinclude each of 6-MSITCs, docosahexaenoic acid (DHA), curcumin, andisorhamnetin alone or in combination of two or more.

The neuron activator of the present embodiment may have a combination ofthe following components:

-   -   6-MSITCs and DHA,    -   6-MSITCs and curcumin, or    -   6-MSITCs and isorhamnetin.

The neuron activator of the present embodiment may further contain anadditive. As the additive, for example, an excipient, a disintegrant, abinder, an antioxidant, a coating agent, a coloring agent, a corrigent,a surfactant, a plasticizer and the like can be blended.

Also, in the neuron activator of the present embodiment, antiallergicagents, cooling agents, vitamines, and other crude drugs can be blendedas long as the effect of the neuron activator is not impaired.

The neuron activator of the present embodiment may be contained infoods, quasi-drugs, and pharmaceuticals.

The form of foods containing the neuron activator of the presentembodiment is not limited. Specific examples of food forms includegeneral foods, general drinks, supplements, health foods, specialpurpose foods, foods with health claims such as foods with functionclaims and foods for specified health, soft drinks, tea drinks, healthdrinks, alcoholic beverages such as wines, confectioneries, cookedrices, breads, noodles, side dishes, seasonings, and the like.

The usage of quasi-drugs and pharmaceuticals containing the neuronactivator of the present embodiment is not limited. For example, thequasi-drugs and the pharmaceuticals may be used as internal/externalpreparations.

The dosage form of quasi-drugs and pharmaceuticals containing the neuronactivator of the present embodiment is not limited. Example dosage formsinclude capsules, tablets, powders, granules, solutions, and the like.

The neuron activator of the present embodiment includes at least oneselected from the group consisting of a dopamine production promotor, aneuron extension promotor, and an amyloid β resistance enhancer, and canbe used for inhibiting or treating diseases or symptoms involvingneurons.

The neuron activator of the present embodiment can be used forinhibition or treatment of neurological disorders selected from thegroup consisting of, for example, dementia, type 2 diabetes,Alzheimer-type dementia, diabetes, Parkinson's disease, transmissiblespongiform encephalopathy commonly known as “mad cow disease”, medullarythyroid carcinoma, arrhythmia, arteriosclerosis, rheumatoid arthritis,aortic medial amyloid, prolactinomas, familial amyloid polyneuropathy,hereditary non-neuropathic amyloidosis, dialysis amyloidosis, Finnishamyloidosis, lattice corneal dystrophy, cerebral amyloid angiopathy,systemic AL amyloidosis, sporadic inclusion body myositis,pheochromocytoma, osteomyelitis, multiple myeloma, encephalitis,meningitis, pre-Alzheimer's disease, mild cognitive impairment,early-onset Alzheimer's disease, late-stage Alzheimer's disease,age-related dementia, Huntington's disease, multiple sclerosis,amyotrophic lateral sclerosis (ALS or Lou Gehrig's disease), priondisease, Creutzfeldt-Jakob disease, Lewy body disease, Friedreich'sataxia, stroke, genetic brain injury, schizophrenia, depression, bipolardisorder, attention deficit hyperactivity disorder (ADHD), autism,Asperger's syndrome, and Down's syndrome.

The neuron activator of the present embodiment is suitable for thefollowing uses:

-   -   pharmaceutical composition for activating neuron including the        neuron activator,    -   food composition for activating neuron including the neuron        activator,    -   application for producing a neuron activator,    -   application for producing pharmaceutical compositions for        activating neurons including the neuron activator;    -   application for producing food compositions for activating        neurons including the neuron activator;    -   method for improving neurons including administering the neuron        activator to a subject;    -   a method for improving neurons including administering the        pharmaceutical composition for activating neurons to a subject,    -   a method for improving neurons including administering the food        composition for activating neurons to a subject, and    -   use of a composition for producing a neuron activator that        activates neurons, the neuron activator comprising at least one        selected from the group consisting of: a dopamine production        promotor that promotes dopamine production of the neurons, a        neuron extension promotor that promotes extension of the        neurons, and an amyloid β resistance enhancer that enhances        resistance of the neurons against amyloid β, the composition        including 6-methylsulfinylhexyl isothiocyanates or glycosides        thereof, and at least one selected from the group consisting of        unsaturated fatty acid and polyphenol.

[Dopamine Production Promotor]

The neuron activator of the present embodiment may be a dopamineproduction promotor. When the dopamine production promotor of thepresent embodiment includes (A) 6-MSITCs and (B) docosahexaenoic acid(DHA), it is preferable that a molar ratio of (B) DHA to (A) 6-MSITCs is0.2 to 400, more preferably 0.2 to 80, and further preferably 1 to 80.

When the dopamine production promotor of the present embodiment includes(A) 6-MSITCs and (CI) curcumin, it is preferable that a molar ratio of(CI) curcumin to (A) 6-MSITCs is 0.04 to 25, more preferably 0.2 to 25.

When the dopamine production promotor of the present embodiment includes(A) 6-MSITCs and (CII) isorhamnetin, it is preferable that a molar ratioof (CII) isorhamnetin to (A) 6-MSITCs is 0.008 to 5, more preferably0.04 to 0.2.

In these cases, it is possible to more effectively promote the effect ofproducing dopamine from neurons.

The dosage of the dopamine production promotor of the present embodimentis determined in consideration of a patient's age, sex, body weight,usage, dose, and the like. Usage includes oral administration, vascularinjection, external application, and the like. In case of oraladministration, it is preferable that daily dosage of 6-MSITCs in thedopamine production promotor is 10 μg to 100 mg/day, the dosage ofunsaturated fatty acid is 100 mg to 10 g/day, and the dosage ofpolyphenol is 0.1 mg to 10 g/day.

When the usage of the dopamine production promotor of the presentembodiment is vascular injection, it is preferable that the daily dosageof 6-MSITCs in the dopamine production promotor is 1 μg to 5 mg/day, thedosage of unsaturated fatty acid is 1 mg to 100 mg/day, and the dosageof polyphenol is 0.1 μg to 1 mg/day.

The dopamine production promotor of the present embodiment is suitablefor the following uses:

-   -   pharmaceutical composition for promoting dopamine production        including the dopamine production promotor,    -   food composition for promoting dopamine production including the        dopamine production promotor,    -   application for producing the dopamine production promotor,    -   application for producing pharmaceutical compositions for        promoting dopamine production including the dopamine production        promotor,    -   application for producing food compositions for promoting        dopamine production including the dopamine production promotor,    -   a method for promoting dopamine production including        administering the dopamine production promotor to a subject,    -   a method for promoting dopamine production including        administering the pharmaceutical composition for promoting        dopamine production to a subject, and    -   a method for promoting dopamine production including        administering the food composition for promoting dopamine        production to a subject.

[Neuron Extension Promotor]

The neuron activator of the present embodiment may be a neuron extensionpromotor.

When the neuron extension promotor of the present embodiment includes(A) 6-MSITCs and (B) docosahexaenoic acid (DHA), it is preferable that amolar ratio of (B) DHA to (A) 6-MSITCs is 0.2 to 400, more preferably0.2 to 80, and further preferably 0.2 to 16.

When the neuron extension promotor of the present embodiment includes(A) 6-MSITCs and (CI) curcumin, it is preferable that a molar ratio of(CI) curcumin to (A) 6-MSITCs is 0.04 to 25, more preferably 0.04 to 1,further preferably 0.2 to 1.

When the neuron extension promotor of the present embodiment includes(A) 6-MSITCs and (CII) isorhamnetin, it is preferable that a molar ratioof (CII) isorhamnetin to (A) 6-MSITCs is 0.008 to 5, more preferably0.008 to 1.0, further preferably 0.008 to 0.2.

In these cases, it is possible to more effectively promote the effect ofextending neurites.

The dosage of the neuron extension promotor of the present embodiment isdetermined in consideration of a patient's age, sex, body weight, usage,dose, and the like. Usage includes oral administration, vascularinjection, external application, and the like. In case of oraladministration, it is preferable that daily dosage of 6-MSITCs in theneuron extension promotor is 10 μg to 100 mg/day, the dosage ofunsaturated fatty acid is 100 mg to 10 g/day, and the dosage ofpolyphenol is 0.1 mg to 10 g/day.

When the usage of the neuron extension promotor of the presentembodiment is vascular injection, it is preferable that the daily dosageof 6-MSITCs in the neuron extension promotor is 1 μg to 5 mg/day, thedosage of unsaturated fatty acid is 1 mg to 100 mg/day, and the dosageof polyphenol is 0.1 μg to 1 mg/day.

The neuron extension promotor of the present embodiment is suitable forthe following uses:

-   -   pharmaceutical composition for promoting neuron extension        including the neuron extension promotor,    -   food composition for promoting neuron extension including the        neuron extension promotor,    -   application for producing the neuron extension promotor,    -   application for producing pharmaceutical compositions for        promoting neuron extension including the neuron extension        promotor,    -   application for producing food compositions for promoting neuron        extension including the neuron extension promotor,    -   a method for promoting neuron extension including administering        the neuron extension promotor to a subject,    -   a method for promoting neuron extension including administering        the pharmaceutical composition for promoting neuron extension to        a subject, and    -   a method for promoting neuron extension including administering        the food composition for promoting neuron extension to a        subject.

[Amyloid β Resistance Enhancer]

The neuron activator of the present embodiment may be an amyloid βresistance enhancer.

The amyloid β resistance enhancer of the present embodiment includes6-methylsulfinylhexyl isothiocyanates or glycosides thereof.

When the amyloid β resistance enhancer of the present embodimentincludes (A) 6-MSITCs and (B) docosahexaenoic acid (DHA), it ispreferable that a molar ratio of (B) DHA to (A) 6-MSITCs is 0.2 to 400,more preferably 0.2 to 80, and further preferably 1 to 80.

When the amyloid β resistance enhancer of the present embodimentincludes (A) 6-MSITCs and (CI) curcumin, it is preferable that a molarratio of (CI) curcumin to (A) 6-MSITCs is 0.04 to 25, more preferably0.2 to 25.

When the amyloid β resistance enhancer of the present embodimentincludes (A) 6-MSITCs and (CII) isorhamnetin, it is preferable that amolar ratio of (CII) isorhamnetin to (A) 6-MSITCs is 0.008 to 5, morepreferably 0.04 to 0.2.

In these cases, it is possible to more effectively increase resistanceof neurons against amyloid β.

The dosage of the amyloid β resistance enhancer of the presentembodiment is determined in consideration of a patient's age, sex, bodyweight, usage, dose, and the like. Usage includes oral administration,vascular injection, external application, and the like. In case of oraladministration, it is preferable that daily dosage of 6-MSITCs in theamyloid β resistance enhancer is 10 μg to 100 mg/day, the dosage ofunsaturated fatty acid is 100 mg to 10 g/day, and the dosage ofpolyphenol is 0.1 mg to 10 g/day.

When the usage of the amyloid β resistance enhancer of the presentembodiment is vascular injection, it is preferable that the daily dosageof 6-MSITCs in the amyloid β resistance enhancer is 1 μg to 5 mg/day,the dosage of unsaturated fatty acid is 1 mg to 100 mg/day, and thedosage of polyphenol is 0.1 μg to 1 mg/day.

The amyloid β resistance enhancer of the present embodiment is suitablefor the following uses:

-   -   pharmaceutical composition for enhancing resistance against        amyloid β including the amyloid β resistance enhancer,    -   food composition for enhancing resistance against amyloid β        including the amyloid β resistance enhancer,    -   application for producing the amyloid β resistance enhancer,    -   application for producing pharmaceutical compositions for        enhancing resistance against amyloid β including the amyloid β        resistance enhancer,    -   application for producing food compositions for enhancing        resistance against amyloid β including the amyloid β resistance        enhancer,    -   a method for enhancing resistance against amyloid β including        administering the amyloid β resistance enhancer to a subject,    -   a method for enhancing resistance against amyloid β including        administering the pharmaceutical composition for enhancing        resistance against amyloid β to a subject, and    -   a method for enhancing resistance against amyloid β including        administering the food composition for enhancing resistance        against amyloid β to a subject.

EXAMPLES Experimental Example 1

Dopamine production tests of PC12 cells, using various components, werecarried out as follows.

(1) Preparation of Various Components

(a) 6-MSITC (Component 1)

6-MSITC used in the present embodiment was chemically synthesized byKinjirushi Co., Ltd. Particulars of a chemical synthesis method of6-MSITC are described as follows.

The method by Kjaer et. al. was followed in principle. (Kjaer et. al.,Acta Chem. Scand., 11, 1298, 1957). 6-chlorohexanol was refluxed withCH₃—SNa to obtain 6-methylthiohexanol. 6-methylthiohexanol was reactedwith thionyl chloride (SOCl₂) to obtain 6-chlorohexyl methyl sulfide.Then, an amino group was introduced to 6-chlorohexyl methyl sulfide byphthalimide potassium salt using the Gabriel method to generateN-(6-methylthiohexyl)-phthalimide. Hydrazine hydrate was added andrefluxed with N-(6-methylthiohexyl)-phthalimide so as to obtain6-methylthiohexylamine. Then, thiocarbonyl chloride was reacted with6-methylthiohexylamine to obtain 6-methylthiohexyl isothiocyanate.

Further, a methylthio group in the obtained 6-methylthiohexylisothiocyanate was oxidized with m-chloroperbenzoic acid to obtain6-methylsulfinylhexyl isothiocyanate (6-MSITC) (Morimitsu et. al., J.Biol. Chem., 277, 3456, 2002).

6-MSITC involved in the present disclosure is included in Brassicaceaeplants and the like, and can be obtained by solvent extraction orpulverization from these plants.

100 mg of 6-MSITC was dissolved in DMSO (dimethylsulfoxide) solvent toprepare a 6-MSITC solution containing 100 mM of 6-MSITC.

(b) DHA (Component 2)

DHA (manufactured by Nacalai Tesque, Inc., Product No. 14122-64) wasobtained. DHA was extracted from blue fish. 100 mg of DHA was dissolvedin DMSO solvent to prepare a DHA solution containing 100 mM of DHA.

(c) Curcumin (Component 3)

Curcumin (CAS No. 458-37-7, manufactured by Tokyo Chemical Industry Co.,Ltd., Product No. C2302) was obtained. Curcumin is represented by achemical formula below.

This curcumin was synthesized. 67.56 mg of curcumin was dissolved inDMSO solvent to prepare a curcumin solution containing 200 mM ofcurcumin.

(d) Isorhamnetin (Component 4)

Isorhamnetin (manufactured by EXTRASYNTHESE, Product No. 11205) wasobtained. Isorhamnetin was extracted from ginkgo leaves. 10 mg ofisorhamnetin was dissolved in DMSO solvent using a pipette to prepare anisorhamnetin solution containing 10 mM of isorhamnetin.

(2) Preparation of Media

A growth medium A and a differentiation medium B containing thefollowing components were prepared.

(a) Components in Growth Medium A

DMEM (Dulbecco's Modified Eagle Medium, manufactured by Nacalai Tesque,Inc., Product No. 08458-45)

10 wt % of horse serum (manufactured by Thermo Fisher Scientific Inc.,Product No. 16050-122)

5 wt % of bovine serum (manufactured by Thermo Fisher Scientific Inc.,Product No. 10437-028)

1 wt % of penicillin streptomycin (manufactured by Nacalai Tesque, Inc.,Product No. 26253-84)

(b) Components in Differentiation Medium B

DMEM (Dulbecco's Modified Eagle Medium, manufactured by Nacalai Tesque,Inc., Product No. 08458-45)

2 wt % of horse serum (manufactured by Thermo Fisher Scientific Inc.,Product No. 16050-122)

1 wt % of penicillin streptomycin (manufactured by Nacalai Tesque, Inc.,Product No. 26253-84)

(3) PC12 Cell Proliferation

The above growth medium A was added to a flask for cell culture(manufacture by Thai Polypropylene Co., Ltd. (TPP)), and PC12 cells(manufactured by RIKEN, Product No. RCB0009) were further added forgrowth. PC12 cells are pheochromocytomas derived from rat's adrenalmedulla, and are models of neuronal differentiation. When PC12 cellsreached confluence of 80-90%, the grown PC12 cells were seeded in a newflask containing the growth medium A and subcultured. A ratio of theculture medium with the grown cells to the new growth medium A was 1:5(volume ratio). Such passage was repeated at least three times.

(4) PC12 Cell Differentiation

In each well of a 96-well plate, 100 μl of growth medium A containingthe post-passage PC12 cells obtained in the above step (3) at aconcentration of 5×10⁴/ml was seeded. The plate was left overnight atroom temperature so as to stabilize the PC12 cells. The plate wascentrifuged and the PC12 cells were allowed to settle in each well ofthe plate. Supernatants were removed. To each well in which the PC12cells were settled, 100 μl of differentiation medium B was added andstirred, so as to suspend the PC12 cells in the differentiation mediumB.

To the differentiation medium B in each well, NGF (manufactured bySigma-Aldrich, Product No. N2513) was added. A concentration of NGFcontained in the medium in all wells was 50 ng/ml.

Further, each of the components 1 to 4 prepared in the above step (1)was added to the medium in each well so as to achieve variousconcentrations in one kind or in combination of two kinds. Each sampleis numbered 1 to 39. Table 1 shows concentrations of the componentscontained in each sample in the medium in each well.

TABLE 1 (Unit: μM) Sample 6-MSITC curcumin DHA isorhamnetin C 1 0.1 20.5 3 2.5 4 0.1 5 0.5 6 2.5 7 0.5 8 2.5 9 40 10 0.02 11 0.1 12 0.5 130.1 0.1 14 0.1 0.5 15 0.1 2.5 16 0.5 0.1 17 0.5 0.5 18 0.5 2.5 19 2.50.1 20 2.5 0.5 21 2.5 2.5 22 0.1 0.5 23 0.1 2.5 24 0.1 40 25 0.5 0.5 260.5 2.5 27 0.5 40 28 2.5 0.5 29 2.5 2.5 30 2.5 40 31 0.1 0.02 32 0.1 0.133 0.1 0.5 34 0.5 0.02 35 0.5 0.1 36 0.5 0.5 37 2.5 0.02 38 2.5 0.1 392.5 0.5

The plate was placed in a carbon dioxide incubator (5% CO₂, 37° C.), andthe PC12 cells were cultured for 72 hours.

(5) Evaluation of Dopamine Production

A concentration of dopamine in each supernatant was measured.Measurement of dopamine concentration was carried out using ELIZA KIT(manufactured by ImmuSmol, Product No.: BA-E-5300) according to thespecifications. A ratio of dopamine concentration in each supernatantwas expressed as a percentage (%) of a control of which dopamineconcentration in the supernatant is 1. Results of the measurement wereshown in FIG. 1 .

In FIG. 1 , “M”, “C”, “D”, and “I” sequentially mean “6-MSITC”,“curcumin”, “DHA”, and “isorhamnetin”. The same applies to FIGS. 2 to 5. In FIG. 1 , τ means statistically significant. * means thatsynergistic effect was confirmed by combining two components.Synergistic effect herein means that use of two components incombination can produce more amount of dopamine than a sum of amounts ofdopamine produced when each component is used alone.

As shown in FIG. 2 , dopamine-producing ability was enhanced bycontaining any one of 6-MSITC, curcumin, DHA, and isorhamnetin in themedium, as compared to a case without these components. Dopamineproduction effect of 6-MSITC was higher than those of curcumin, DHA, andisorhamnetin.

When 0.5 μM or 2.5 μM of 6-MSITC was added to the medium, the amount ofdopamine production produced by the PC12 cells was higher than thecontrol. When 0.1 μM or 2.5 μM of curcumin was added to the medium, theamount of dopamine production produced by the PC12 cells was higher thanthe control. When 0.5 μM or 40 μM of DHA was added to the medium, theamount of dopamine production produced by the PC12 cells was higher thanthe control. When 0.02 μM, 0.1 μM, or 0.5 μM of isorhamnetin was addedto the medium, the amount of dopamine production produced by the PC12cells was higher than the control.

There was a tendency that the amount of dopamine production was higherwhen 6-MSITC is combined with other components, as compared to a case inwhich one type of component was used. In combination of 6-MSITC andcurcumin, the amount of dopamine production was higher when 6-MSITC is0. 1 to 2.5 μM and curcumin is 0.1 to 2.5 μM. In combination of 6-MSITCand DHA, the amount of dopamine production was higher when 6-MSITC is0.1 to 2.5 μM, and DHA is 0.5 to 40 μM. In combination of 6-MSITC andisorhamnetin, the amount of dopamine production was higher when 6-MSITCis 0.1 to 2.5 μM, and isorhamnetin is 0.02 to 0.5 μM.

Experimental Example 2

Toxicity of each component to PC12 cells was investigated using an MTT(3-(4,5-di-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, yellowtetrazole) reagent.

In order to investigate toxicity of each component to PC12 cells, thePC12 cells were cultured in the same manner as in the above steps (1) to(4) of Experimental example 1, except for components added to themedium. The component added to the differentiation medium B in each wellof (4) is any one of 6-MSITC (Component 1), curcumin (Component 3), DHA(Component 2), or isorhamnetin (Component 4). Concentrations of therespective components in the differentiation medium B were 0 (control),2.5 μM, 5 μM, 10 μM, 20 μM, 40 μM, 80 μM, and 160 μM with respect to6-MSITC (Component 1), 0 (control), 2.5 μM, 5 μM, 10 μM, 20 μM, and 40μM with respect to curcumin (Component 3), 0 (control), 2.5 μM, 5 μM, 10μM, 20 μM, 40 μM, 80 μM, and 160 μM with respect to DHA (Component 2),and 0 (control), 0.02 μM, 0 1 μM, 0.5 μM, 1 μM, 2.5 μM, 5 μM, and 10 μMwith respect to isorhamnetin (Component 4).

After the PC12 cells were cultured for 72 hours in the above step (4)PC12 cell differentiation of Experimental example 1, 10 μl/well of MTTreagent (manufactured by Nacalai Tesque, Inc., Product No. 23547-21, MTT5 mg/ml in a phosphate buffered saline) was added to the medium in eachwell. Further, the plate was placed in a carbon dioxide incubator (5%CO₂, 37° C.), and the PC12 cells were cultured for 4 hours.

The plate was centrifuged to allow the cells to settle in the wells.Supernatants were removed. To each well, 100 μl/well of DMSO was added,shaken and stirred to suspend the PC12 wells in DMSO to obtain a cellsolution.

Absorbance of 490 nm was measured for the cell solution in each well. Afraction, of which denominator is absorbance of the cell solution of thecontrol and numerator is absorbance of the cell solution of PC12 cellscultured in the culture medium including each sample, was converted intoa decimal number, and a resulting value was shown as an MTT assay.Results of measurements in case of using 6-MSITC, curcumin, DHA, andisorhamnetin are sequentially shown in FIGS. 2, 3, 4, and 5 .

In case of using 6-MSITC, curcumin, DHA, and isorhamnetin, the MTT assaywas higher than the case of not using them (control). In view of theabove, it was found that toxicity of 6-MSITC, curcumin, DHA, andisorhamnetin is low.

Experimental Example 3

Neurite extension tests of PC12 cells, using various components, werecarried out as follows.

The above steps (1) Preparation of various components and (2)Preparation of media in Experimental example 1 were carried out toprepare 6-MSITC (Component 1), DHA (Component 2), curcumin (Component3), the growth medium A, and differentiation medium B.

(3) PC12 Cell Proliferation

The above growth medium A was added to a flask for cell culture(manufactured by TPP), and PC12 cells (manufactured by RIKEN, ProductNo. RCB0009) were further added for growth. PC12 cells arepheochromocytomas derived from rat's adrenal medulla, and are models ofneuronnal differentiation. When PC12 cells reached confluence of 80-90%,the grown PC12 cells were seeded in a new flask containing the growthmedium A and subcultured. A ratio of the culture medium with the growncells to the new growth medium A was 1:5 (volume ratio). Such passagewas repeated at least three times.

(4) PC12 Cell Differentiation

In each well of a 96-well plate, 100 μl of growth medium A containingthe post-passage PC12 cells obtained in the above step (3) at aconcentration of 5×10⁴/ml was seeded. The plate was left overnight atroom temperature so as to stabilize the PC12 cells. The plate wascentrifuged and the PC12 cells were allowed to settle in each well ofthe plate. Supernatants were removed. To each well in which the PC12cells were settled, 100 μl of differentiation medium B was added andstirred, so as to suspend the PC12 cells in the differentiation mediumB.

To the differentiation medium B in each well, NGF (manufactured bySigma-Aldrich, Product No. N2513) was added. A concentration of NGFcontained in the medium in all wells was 50 ng/ml.

Further, each of the components 1 to 4 prepared in the above step (1) ofExperimental example 1 was added to the medium in each well so as toachieve various concentrations in one kind or in combination of twokinds. Each sample is numbered 1 to 39. Table 2 shows concentrations ofthe components contained in each sample in the medium in each well.

TABLE 2 (Unit: μM) Sample 6-MSITC curcumin DHA isorhamnetin C 1 0.1 20.5 3 2.5 4 0.1 5 0.5 6 2.5 7 0.5 8 2.5 9 40 10 0.02 11 0.1 12 0.5 130.1 0.1 14 0.1 0.5 15 0.1 2.5 16 0.5 0.1 17 0.5 0.5 18 0.5 2.5 19 2.50.1 20 2.5 0.5 21 2.5 2.5 22 0.1 0.5 23 0.1 2.5 24 0.1 40 25 0.5 0.5 260.5 2.5 27 0.5 40 28 2.5 0.5 29 2.5 2.5 30 2.5 40 31 0.1 0.02 32 0.1 0.133 0.1 0.5 34 0.5 0.02 35 0.5 0.1 36 0.5 0.5 37 2.5 0.02 38 2.5 0.1 392.5 0.5

The plate was placed in a carbon dioxide incubator (5% CO₂, 37° C.), andthe PC12 cells were cultured for 72 hours.

(5) Evaluation of Cell Extension

After culturing in the above step (4), the plate was centrifuged toallow the cells to settle in the wells. Supernatants were removed. Threemicroscopic images (bright field, ×10 images, three wells per well) ofPC12 cells settled in each well were taken. The shape of the whole PC12cells in the images was observed. A shown in FIG. 6 , when PC12 cellsundergo differentiation, a neurite 2 extends from a cell body 1. Thetotal number of PC12 cells, and the number of cells having the neurite 2with a length L2 were counted. The length L2 is a longer length than alonger diameter L1 of the cell body 1. The number of cells having theneurite with the length L2 was divided by the total number of cells toobtain an extension percentage of the PC12 cells. In each image, atleast 80 PC12 cells appeared. The total number of the PC12 cellsappearing in all images was 720 or more. The extension percentage wasexpressed by an average value of all PC12 cells appearing in all images.The extension percentage of each PC12 cell was shown in FIG. 7 . In FIG.7 , “M”, “C”, “D”, and “I” sequentially mean “6-MSITC”, “curcumin”,“DHA”, and “isorhamnetin”. The same applies to FIGS. 8 to 11. In FIG. 7, τ means statistically significant. * means that synergistic effect wasconfirmed by combining two components. Synergistic effect herein meansthat use of two components in combination can increase the extensionpercentage as compared to a sum of extension percentages when eachcomponent is used alone.

As shown in FIG. 7 , neurite extension effect was enhanced by containingany one of 6-MSITC, curcumin, DHA, and isorhamnetin in the medium, ascompared to a case without these components. Neurite extension effect of6-MSITC was higher than those of curcumin, DHA, and isorhamnetin.

When 0.1 μM, 0.5 μM, or 2.5 μM of 6-MSITC was added to the medium,significant extension enhancement was observed for PC12 cells. When 0.1μM, 0.5 μM, or 2.5 μM of curcumin was added to the medium, significantextension enhancement was observed for PC12 cells. When 0.5 μM, 2.5 μM,or 40 μM of DHA was added to the medium, significant extensionenhancement was observed for PC12 cells. When 0.02 μM, 0.1 μM, or 0.5 μMof isorhamnetin was added to the medium, significant extensionenhancement was observed for PC12 cells.

As compared to the case of using only one type of component, theextension percentage was higher when two types including 6-MSITC and theother component are combined. In combination of 6-MSITC and curcumin,the extension percentage effectively increased when 6-MSITC is 0.1 to2.5 μM and curcumin is 0.1 to 2.5 μM. In combination of 6-MSITC and DHA,the extension percentage effectively increased when 6-MSITC is 0.1 to2.5 μM and DHA is 0.5 to 40 μM. In combination of 6-MSITC andisorhamnetin, the extension percentage effectively increased when6-MSITC is 0.1 μM and 2.5 μM and isorhamnetin is 0.02 to 0.5 μM.

Experimental Example 4

Toxicity of each component to PC12 cells was investigated using an MTT(3-(4,5-di-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, yellowtetrazole) reagent.

In order to investigate toxicity of each component to PC12 cells, thePC12 cells were cultured in the same manner as in the above steps (1) to(4) of Experimental example 3, except for components added to themedium. The component added to the differentiation medium B in each wellin the above step (4) is any one of 6-MSITC (Component 1), curcumin(Component 3), DHA (Component 2), or isorhamnetin (Component 4).Concentrations of the respective components in the differentiationmedium B were 0 (control), 2.5 μM, 5 μM, 10 μM, 20 μM, 40 μM, 80 μM, and160 μM with respect to 6-MSITC (Component 1), 0 (control), 2.5 μM, 5 μM,10 μM, 20 μM, and 40 μM with respect to curcumin (Component 3), 0(control), 2.5 μM, 5 μM, 10 μM, 20 μM, 40 μM, 80 μM, and 160 μM withrespect to DHA (Component 2), and 0 (control), 2.5 μM, 5 μM, 10 μM, and20 μM with respect to isorhamnetin (Component 4).

After the PC12 cells were cultured for 72 hours in the above step (4)PC12 cell differentiation of Experimental example 3, 10 μl/well of MTTreagent (manufactured by Nacalai Tesque, Inc., Product No. 23547-21, MTT5 mg/ml in a phosphate buffered saline) was added. Further, the platewas placed in a carbon dioxide incubator (5% CO₂, 37° C.), and the PC12cells were cultured for 4 hours.

The plate was centrifuged to allow the cells to settle in the wells.Supernatants were removed. To each well, 100 μl/well of DMSO was added,shaken and stirred to suspend the PC12 wells in DMSO to obtain a cellsolution.

Absorbance of 490 nm was measured for the cell solution in each well. Afraction, of which denominator is absorbance of the cell solution of thecontrol and numerator is absorbance of the cell solution of PC12 cellscultured in the culture medium including each sample, is converted intoa decimal number, and a resulting value was shown as an MTT assay.Results of measurements in case of using 6-MSITC, curcumin, DHA, andisorhamnetin are sequentially shown in FIGS. 8, 9, 10, and 11 .

In case of using 6-MSITC, curcumin, DHA, and isorhamnetin, the MTT assaywas higher than the case of not using them (control). In view of theabove, it was found that toxicity of 6-MSITC, curcumin, DHA, andisorhamnetin is low.

Experimental Example 5

Resistance Test of Neurons Against Amyloid β

The above steps (1) Preparation of various components and (2)Preparation of media in Experimental example 1 were carried out toprepare (a) 6-MSITC (Component 1), (b) DHA (Component 2), (c) curcumin(Component 3), the growth medium A and the differentiation medium B.

(3) PC12 Cell Proliferation

The above growth medium A was added to a flask for cell culture(manufactured by TPP), and PC12 cells (manufactured by RIKEN, ProductNo. RCB0009) were further added for growth. PC12 cells arepheochromocytomas derived from rat's adrenal medulla, and are models ofneuronnal differentiation. When PC12 cells reached confluence of 80-90%,the grown PC12 cells were seeded in a new flask containing the growthmedium A and subcultured. A ratio of the culture medium with the growncells to the new growth medium A was 1:5 (volume ratio). Such passagewas repeated at least three times.

(4) PC12 Cell Differentiation

In each well of a 96-well plate, 100 μl of growth medium A containingthe post-passage PC12 cells obtained in the above step (3) at aconcentration of 5×10⁴/ml was seeded. The plate was left overnight atroom temperature so as to stabilize the PC12 cells. The plate wascentrifuged and the PC12 cells were allowed to settle in each well ofthe plate. Supernatants were removed. To each well in which the PC12cells were settled, 100 μl of differentiation medium B was added andstirred, so as to suspend the PC12 cells in the differentiation mediumB.

To the medium in each well, NGF (manufactured by Sigma-Aldrich, ProductNo. N2513) was added. A concentration of NGF contained in the medium inall wells was 50 ng/ml. The well plate was placed in a carbon dioxideincubator (5% CO₂, 37° C.), and the PC12 cells were cultured for 72hours.

Each of the components 1 to 4 prepared in the above step (1) ofExperimental example 1 was added to the medium in each well so as toachieve various concentrations in one kind or in combination of twokinds. Each sample is numbered 1 to 38. The differentiation medium B wasused for concentration adjustment. Table 3 shows concentrations of thecomponents contained in each sample in the medium in each well. Further,amyloid β (manufactured by Ana Spec, Inc., Item No. AS-24224) was addedto the medium in each well. A concentration of amyloid β in the mediumis 1 μmol/L. In addition to the above samples, a sample in which neitherthe components 1 to 4 nor amyloid β was added to the medium was referredto as “control”. Also, a sample in which amyloid β was added to themedium but the components 1 to 4 were not was referred to as “AMB”.

Thereafter, the well plate was placed in a carbon dioxide incubator (5%CO₂, 37° C.), and the PC12 cells were cultured for 24 hours.

TABLE 3 (Unit: μM) Sample 6-MSITC curcumin DHA isorhamnetin Control(amyloid β not added) AMB 1 0.1 2 0.5 3 2.5 4 0.1 5 0.5 6 2.5 7 0.5 82.5 9 0.02 10 0.1 11 0.5 12 0.1 0.1 13 0.1 0.5 14 0.1 2.5 15 0.5 0.1 160.5 0.5 17 0.5 2.5 18 2.5 0.1 19 2.5 0.5 20 2.5 2.5 21 0.1 0.5 22 0.12.5 23 0.1 40 24 0.5 0.5 25 0.5 2.5 26 0.5 40 27 2.5 0.5 28 2.5 2.5 292.5 40 30 0.1 0.02 31 0.1 0.1 32 0.1 0.5 33 0.5 0.02 34 0.5 0.1 35 0.50.5 36 2.5 0.02 37 2.5 0.1 38 2.5 0.5

(5) Amyloid β Neurotoxicity Resistance Test

Resistance of PC12 cells to amyloid β was investigated using an MTT(3-(4,5-di-methylthiazol-2-yl)-2,5-diphenyltetrazolium bromide, yellowtetrazole) reagent.

10 μl/well of MTT reagent (manufactured by Nacalai Tesque, Inc., ProductNo. 23547-21, MTT 5 mg/ml in phosphate buffered saline) was added afterthe above step (4) PC12 cell differentiation. Further, the plate wasplaced in a carbon dioxide incubator (5% CO₂, 37° C.), and the PC12cells were cultured for 4 hours.

The plate was centrifuged to allow the cells to settle in the wells.Supernatants were removed. To each well, 100 μl/well of DMSO was added,shaken and stirred to suspend the PC12 wells in DMSO to obtain a cellsolution.

Absorbance of 490 nm was measured for the cell solution in each well. Afraction, of which denominator is absorbance of the cell solution of thecontrol and numerator is absorbance of the cell solution of PC12 cellscultured in the culture medium including each sample, was converted intoa decimal number, and a resulting value was shown as an MTT assay.Results of measurements are shown in FIG. 12 .

In FIG. 12 , “M”, “C”, “D”, and “I” sequentially mean “6-MSITC”,“curcumin”, “DHA”, and “isorhamnetin”. The same applies to FIG. 13 .

As shown in FIG. 12 , as compared to the case of the medium withoutamyloid β (control), the MTT assay significantly decreased when the PC12cells were cultured in the medium containing only amyloid β (AMB). Theeffect of enhancing amyloid β resistance of PC12 cells by 6-MSITC washigher than those of curcumin, DHA, and isorhamnetin. As compared to thecase of culturing the cells in the medium containing only amyloid β(AMB), the MTT assay was higher when 6-MSITC was combined with curcumin,DHA or isorhamnetin and added to the medium together with amyloid β.

Experimental Example 6

Resistance Test of Neurons Against Hydrogen Peroxide

In Experimental example 6, resistance of PC12 cells against hydrogenperoxide was tested. The test method is the same as that of Experimentalexample 5, except that hydrogen peroxide was added to thedifferentiation medium B, instead of amyloid β in Experimental example 5above. A concentration of hydrogen peroxide in the differentiationmedium B was 100 μM. Results of the experiment were shown in FIG. 13 .

As shown in FIG. 13 , as compared to a case of culturing in the mediumwithout hydrogen peroxide (control), the MTT assay significantlydecreased when the PC12 cells were cultured in the medium containingonly hydrogen peroxide (H₂O₂). When 6-MSITC, curcumin, DHA orisorhamnetin was added alone, or when a combination of 6-MSITC andcurcumin, DHA or isorhamnetin was added to the medium, the MTT assayshowed a value without problem.

In view of the above experiments, it was confirmed that there is afunction of protecting neurons against internally produced amyloid β andhydrogen peroxide when 6-MSITC and curcumin, DHA, or isorhamnetin arecombined, as compared to the case without these components and the casein which these components are used alone.

The influence of amyloid β on neurons is considered to be related toreactive oxygen species. Reactive oxygen species are known to takevarious forms such as single oxygen, hydrogen peroxide, lipid peroxideand the like due to its high reactivity, and increase damage to cells.Having resistance against both amyloid β and hydrogen peroxide is usefulsince there is a possibility that disorders by these various activeoxygen species can be widely inhibited.

What is claimed is:
 1. A method of activating neurons by promotingdopamine production of the neurons, promoting extension of the neurons,or enhancing resistance of the neurons against amyloid β, comprisingadministering an effective amount of a neuron activator to a subject inneed thereof, the neuron activator including 6-methylsulfinylhexylisothiocyanates or glycosides thereof, and at least one selected fromthe group consisting of unsaturated fatty acid and polyphenol.
 2. Themethod according to claim 1, wherein the unsaturated fatty acid includesω-3 fatty acid.
 3. The method according to claim 2, wherein the ω-3fatty acid includes at least one selected from the group consisting ofdocosahexaenoic acid and eicosapentaenoic acid.
 4. The method accordingto claim 2, wherein the ω-3 fatty acid is extracted from fish andshellfish and/or fish oil.
 5. The method according to claim 1, whereinthe polyphenol includes at least one selected from the group consistingof curcuminoid and flavonoid.
 6. The method according to claim 5,wherein the curcuminoid includes curcumin.
 7. The method according toclaim 5, wherein the curcuminoid is extracted from turmeric.
 8. Themethod according to claim 5, wherein the flavonoid includesisorhamnetin.